Of the two compounds SiF4 and SF4, which is polar and which is nonpolar?

Verified step by step guidance

1. Step 1: Determine the Lewis structure for each molecule. The Lewis structure is a graphical representation of the molecule that shows how the electrons are arranged among the atoms of the molecule.
2. Step 2: Determine the molecular geometry of each molecule. The molecular geometry is the three-dimensional arrangement of the atoms that constitute a molecule. It includes the general shape of the molecule as well as bond lengths and bond angles.
3. Step 3: Determine the electronegativity of the atoms in each molecule. Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. The Pauling scale is commonly used to quantify electronegativity.
4. Step 4: Determine if there is a net dipole moment in each molecule. A molecule will be polar if there is a net dipole moment, which occurs when there is an imbalance in the electron distribution in the molecule. This is determined by both the molecular geometry and the difference in electronegativity between the atoms.
5. Step 5: Based on the above steps, determine which molecule is polar and which is nonpolar. A molecule is polar if it has a net dipole moment, and nonpolar if it does not.

Key Concepts

Molecular Geometry

Molecular geometry refers to the three-dimensional arrangement of atoms within a molecule. The shape of a molecule is determined by the number of bonding pairs and lone pairs of electrons around the central atom. For SiF4, the geometry is tetrahedral, while SF4 has a seesaw shape due to the presence of one lone pair, which affects the distribution of charge.

Polarity

Polarity in molecules arises from the uneven distribution of electron density, leading to a dipole moment. A molecule is polar if it has a net dipole moment, which occurs when there is an asymmetrical arrangement of polar bonds. In the case of SF4, the seesaw shape creates an uneven distribution of charge, making it polar, while SiF4, being symmetrical, is nonpolar.

Electronegativity

Electronegativity is a measure of an atom's ability to attract and hold onto electrons in a bond. In the context of SiF4 and SF4, fluorine is highly electronegative, creating polar bonds with silicon and sulfur. The difference in electronegativity between the central atom and fluorine contributes to the overall polarity of the molecule, influencing the molecular geometry and dipole moment.